The present invention relates to pharmaceutical compositions, particularly to pharmaceutical compositions containing ZD6474 or a pharmaceutically-acceptable salt thereof, to processes for the preparation of said pharmaceutical compositions, to said pharmaceutical compositions for use in the production of an antiangiogenic and/or vascular permeability reducing effect in a warm-blooded animal such as a human, to the use of said pharmaceutical compositions in the manufacture of a medicament for use in the production of an antiangiogenic and/or vascular permeability reducing effect in a warm-blooded animal such as a human and to a method for the production of an antiangiogenic and/or vascular permeability reducing effect in a warm-blooded animal such as a human which comprises the administration of such a pharmaceutical composition.
Normal angiogenesis plays an important role in a variety of processes including embryonic development, wound healing and several components of female reproductive function. Undesirable or pathological angiogenesis has been associated with disease states including diabetic retinopathy, psoriasis, cancer, rheumatoid arthritis, atheroma, Kaposi's sarcoma and haemangioma (Fan et al, 1995, Trends Pharmacol. Sci. 16: 57-66; Folkman, 1995, Nature Medicine 1: 27-31). Alteration of vascular permeability is thought to play a role in both normal and pathological physiological processes (Cullinan-Bove et al, 1993, Endocrinology 133: 829-837; Senger et al, 1993, Cancer and Metastasis Reviews, 12: 303-324). Several polypeptides with in vitro endothelial cell growth promoting activity have been identified including, acidic and basic fibroblast growth factors (aFGF & bFGF) and vascular endothelial growth factor (VEGF). By virtue of the restricted expression of its receptors, the growth factor activity of VEGF, in contrast to that of the FGFs, is relatively specific towards endothelial cells. Recent evidence indicates that VEGF is an important stimulator of both normal and pathological angiogenesis (Jakeman et al, 1993, Endocrinology, 133: 848-859; Kolch et al, 1995, Breast Cancer Research and Treatment, 36:139-155) and vascular permeability (Connolly et al, 1989, J. Biol. Chem. 264: 20017-20024). Antagonism of VEGF action by sequestration of VEGF with antibody can result in inhibition of tumour growth (Kim et al, 1993, Nature 362: 841-844).
Receptor tyrosine kinases (RTKs) are important in the transmission of biochemical signals across the plasma membrane of cells. These transmembrane molecules characteristically consist of an extracellular ligand-binding domain connected through a segment in the plasma membrane to an intracellular tyrosine kinase domain. Binding of ligand to the receptor results in stimulation of the receptor-associated tyrosine kinase activity which leads to phosphorylation of tyrosine residues on both the receptor and other intracellular molecules. These changes in tyrosine phosphorylation initiate a signalling cascade leading to a variety of cellular responses. To date, at least nineteen distinct RTK subfamilies, defined by amino acid sequence homology, have been identified. One of these subfamilies is presently comprised by the fms-like tyrosine kinase receptor, Flt-1 (also referred to as VEGFR-1), the kinase insert domain-containing receptor, KDR (also referred to as VEGFR-2 or Flk-1), and another fms-like tyrosine kinase receptor, Flt-4. Two of these related RTKs, Flt-1 and KDR, have been shown to bind VEGF with high affinity (De Vries et al, 1992, Science 255: 989-991; Terman et al, 1992, Biochem. Biophys. Res. Comm. 1992, 187: 1579-1586). Binding of VEGF to these receptors expressed in heterologous cells has been associated with changes in the tyrosine phosphorylation status of cellular proteins and calcium fluxes.
VEGF is a key stimulus for vasculogenesis and angiogenesis. This cytokine induces a vascular sprouting phenotype by inducing endothelial cell proliferation, protease expression and migration, and subsequent organisation of cells to form a capillary tube (Keck, P. J., Hauser, S. D., Krivi, G., Sanzo, K., Warren, T., Feder, J., and Connolly, D. T., Science (Washington D.C.), 246: 1309-1312, 1989; Lamoreaux, W. J., Fitzgerald, M. E., Reiner, A., Hasty, K. A., and Charles, S. T., Microvasc. Res., 55: 29-42, 1998; Pepper, M. S., Montesano, R., Mandroita, S. J., Orci, L. and Vassalli, J. D., Enzyme Protein, 49: 138-162, 1996.). In addition, VEGF induces significant vascular permeability (Dvorak, H. F., Detmar, M., Claffey, K. P., Nagy, J. A., van de Water, L., and Senger, D. R., (Int. Arch. Allergy Immunol., 107: 233-235, 1995; Bates, D. O., Heald, R. I., Curry, F. E. and Williams, B. J. Physiol. (Lond.), 533: 263-272, 2001), promoting formation of a hyper-permeable, immature vascular network which is characteristic of pathological angiogenesis.
It has been shown that activation of KDR alone is sufficient to promote all of the major phenotypic responses to VEGF, including endothelial cell proliferation, migration, and survival, and the induction of vascular permeability (Meyer, M., Clauss, M., Lepple-Wienhues, A., Waltenberger, J., Augustin, H. G., Ziche, M., Lanz, C., Büttner, M., Rziha, H-J., and Dehio, C., EMBO J., 18: 363-374, 1999; Zeng, H., Sanyal, S. and Mukhopadhyay, D., J. Biol. Chem., 276: 32714-32719, 2001; Gille, H., Kowalski, J., Li, B., LeCouter, J., Moffat, B, Zioncheck, T. F., Pelletier, N. and Ferrara, N., J. Biol. Chem., 276: 3222-3230, 2001).
Quinazoline derivatives which are inhibitors of VEGF receptor tyrosine kinase are described in International Patent Applications Publication Nos. WO 98/13354 and WO 01/32651. In WO 98/13354 and WO 01/32651 compounds are described which possess activity against VEGF receptor tyrosine kinase (VEGF RTK) whilst possessing some activity against epidermal growth factor (EGF) receptor tyrosine kinase (EGF RTK).
ZD6474 is 4-(4-bromo-2-fluoroanilino)-6-methoxy-7-(1-methylpiperidin-4-ylmethoxy)quinazoline:

ZD6474 falls within the broad general disclosure of WO 98/13354 and is exemplified in WO 01/32651 (Example 2 therein). ZD6474 is a potent inhibitor of VEGF RTK and also has some activity against EGF RTK. ZD6474 has been shown to elicit broad-spectrum anti-tumour activity in a range of models following once-daily oral administration (Wedge S. R., Ogilvie D. J., Dukes M. et al, Proc. Am. Assoc. Canc. Res. 2001; 42: abstract 3126).
In WO 98/13354, Example 77 therein describes some pharmaceutical dosage forms of a compound of formula I. In WO 01/32651, Example 11 therein describes similar pharmaceutical dosage forms of a compound of formula I. WO 01/32651 also describes the formulation of compounds that was used for dosing rats in the 14 day toxicity test: “Compounds were initially formulated by suspension in a 1% (v/v) solution of polyoxyethylene (20) sorbitan mono-oleate in deionised water, by ball-milling at 4° C. overnight (at least 15 hours). Compounds were re-suspended by agitation immediately prior to dosing.”
In general, pharmaceutical compositions of the compounds of formula I in WO 01/32651 may be prepared in a conventional manner using conventional excipients. An oral dosage form (e.g. tablet, capsule, granules, pellets, lozenges etc.) of ZD6474 was sought for clinical trials and commercial use.
In developing an oral dosage form, particularly tablets, one must consider the mechanical properties of the active pharmaceutical ingredient and of any proposed excipients.
The mechanical properties of materials such as powders may be described in terms of the following characteristics:                (a) Hardness, or resistance to deformation, which can be measured by an indentation hardness test;        (b) Yield pressure (denoted Py and also known as yield stress), that is the point at which plastic deformation occurs, which can be measured by compaction studies;        (c) Strain Rate Sensitivity (SRS), that is the percent increase in yield pressure from slow to fast punch velocity, which can be measured by compaction studies; and        (d) Modulus of Elasticity, that is the ratio of stress to elongation (strain), which can be measured by numerous methods that are well known to a person skilled in the art of formulation.        
Materials can, in general, be classified by the way in which they deform under compressive force, either by brittle fracture or by plastic deformation. The degree of deformation for a brittle material is independent of the rate and duration of the compression event (that is the compression applied), giving a strain rate sensitivity value for such materials of 0% (zero %). Deformation of a plastic material is dependent on the rate and duration of the compression event and this is described by the strain rate sensitivity.
When developing an oral dosage form, particularly a tablet formulation, it is usual to use a mixture of powders: some with brittle character to minimise the strain rate sensitivity and some with moderate plastic character to increase the surfaces available to form bonds during compression.
Tablet presses used in commercial manufacture typically run at much faster speeds than those used in research and development. As the speed of a press increases, the duration of the compression event (that is the period for which compression is applied; also known as dwell time) decreases. This has no impact on the compression of a brittle material with an SRS of say 0%, but for a plastic material, for which the deformation is dependent on the rate and duration of compression, a faster press would typically produce softer tablets. Therefore, an excess of plastic material in a formulation can lead to difficulties on scale up to the faster compression machines used in full scale production.
ZD6474 is an extremely plastic material with a yield pressure of 22 MPa and with a very high strain rate sensitivity of 197%. This makes the formulation of a solid oral dosage form of ZD6474 difficult. For example in tablet manufacture these properties can lead to problems in achieving suitably hard tablets, particularly when scaling up from the relatively slow tablet machines (with correspondingly long compression events) used in research and development for small numbers of tablets, to the faster compression machines (with short compression events) used in full scale commercial manufacture.